Security will be heightened by another notch at major airports in the country from Monday ahead of the two-day Nuclear Security Summit, which is scheduled to begin on March 26 in Seoul.

The precautions will remain in place through March 27 at Gimpo, Gimhae and Cheongju international airports, and through March 28 for Incheon, Korea's main air gateway.

The Ministry of Land, Transport and Maritime Affairs requested on Thursday that passengers taking international flights arrive at the airports three hours before boarding during the period.

Korea City Air Terminal at COEX, which is hosting the summit, normally offers a service allowing passengers to check their baggage and obtain their boarding passes ahead of arriving at their departing airport. However, this service will be suspended during the summit.